This invention represents the marrying and adaptation of several concepts that give the final product a wide range of uses. The ability to function under a wide range of applications affords the instant deployment system and apparatus, including using a multifunctional head with a universal connect/disconnect (UCD) tool, significant speed advantages, especially when using coiled tubing for numerous and differing applications in quick succession. Among the numerous differing applications might be coiled tubing drilling, coiled tubing directional drilling and coiled tubing perforating. The system and apparatus is particularly applicable for all operations performed in whole or in part in a live well using long tools. The system and apparatus might be used for running out of a live well even if running in were performed in a dead well. The system has particular application for sour wells as the system significantly permits making and breaking joints using remote control, largely "hands free".
Components of a multifunctional head system that can advantageously render its use universal include a fatigue resistant, high strength coiled tubing connector tool, a wireline anchor, an electrical bulkhead, a release tool and check valves, all combined with a rotationally insensitive, "hands free" deployment system that is fast to connect and disconnect. Such a multifunctional head system can offer a single coiled tubing head for use with fishing operations, drilling operations (with and without wireline), electric logging operations, perforating and simple circulating procedures. Field trials indicate that this invention can save significant time during coiled tubing drilling operations. While it takes several hours to connect a coiled tubing head, with the instant multifunctional head this operation may only be required once per job, not the normal 3 to 5 times.
There are connector tools available commercially that can connect a bottomhole assembly (BHA) to a string of coiled tubing. There are also separate tools for anchoring wireline, for providing means of disconnecting from the coil, for providing check valve functions and for providing tool connections. There are, however, to our knowledge no tools available that purport to combine these functions in a universal coiled tubing head. Existing combinations of presently commercially available tools can only be effected and used in narrowly constrained conditions.
The present invention, thus, solves one problem of having to use different coiled tubing heads for each different operation to be carried out.
This is particularly beneficial in a typical coiled tubing drilling operation where the sequence of operations would typically be:
Pull a plug PA1 Drill out the shoe using a non-directional drilling string PA1 Drill a directional hole using a directional drill string PA1 Log the hole
(Line the hole)
These operations are traditionally separated by the time consuming work of reheading the coiled tubing. With the present multifunctional head invention these operations could now follow on from each other in a fast, efficient manner, requiring only a quick connector to be broken and remade between runs.
Design for a UCD and its system of deployment was originally developed in conjunction with directional drilling strings. It was subsequently modified for use with perforating guns. Another objective of the developing deployment system and apparatus was to provide a means for quickly connecting and disconnecting tools inside a live wellhead without the need for human, manual intervention. Beneficially, if the riser is open to well fluid and the well is sour, personnel should be able to perform as much as possible of the operation from a remote distance.
Existing systems that have been proposed to achieve this goal are relatively fragile, complicated and expensive. One unique feature of the present invention comprises the use of external pressure to effect tool connection and disconnection. Such use of external pressure has the advantage of permitting the use of simpler downhole components and standard oilfield blow out preventors (BOP's) for surface handling. A second feature of the invention permits making and breaking joints without rotation or rotational alignment.
Two deployment system embodiments have been tested so far. One uses a single external port, referenced to an internal pressure. The second uses two external ports, referencing the differential pressure between them. Either pressure sensitive method of connect/disconnect could be used for a variety of coiled tubing operations.
A preferred embodiment of the deployment apparatus utilizes a standard three ram BOP (Texas Oil Tools). The BOP is modified such that the top ram performs a horizontal position adjustment and a vertical height alignment function. Although in the disclosed preferred embodiment two standard BOP rams have been utilized to create a pressure chamber, it is clear that one ram could be modified to provide the necessary sealing around a connector section and to provide a channel for pressure to the connector device.
Several operations in oil and gas wells require the use of quite long tool strings. Two prime examples are perforating tools and drilling tools, as mentioned above. Whereas traditional handling of long tool strings in live well applications has been performed through the use of long risers, such risers are impractical with the very long tool strings. A solution developed for this problem, commonly referred to as "deployment", involves running shorter modular sections of a BHA tool string into a live wellhead and then connecting the successive sections together.
Various methods of achieving deployment for the very long tool strings have been developed. However, these methods either have failed to allow for a true "hands-free" operation, or have resulted in complex mechanisms. The present invention solves this problem by using pressure external to the connector tool to achieve a "hands free" locking/unlocking operation. The use of pressure has the additional advantage of allowing the use of established wellhead pressure control equipment (BOP's), appropriately modified. The methodology of the present invention permits the use of this trusted standard surface equipment and provides in addition for incorporating a rugged, simple downhole connector tool. The result is a connector system and tool suitable for harsh environments, such as the vibrating, dirty environment associated with drilling.
Prior art deployment systems also appear to involve a further problem that may prevent them from being used for drilling operations. This problem is occasioned by the fact that connections in a drill string must withstand torque; otherwise the drill motor spins rather than the bit!
Anti-rotation devices needed in the connector tools have taken many forms, including splines, keys and castelations. All of these solutions to date have required rotational alignment of the connector tool sections before or during connecting. Rotational alignment is not easy in a coil environment as neither half of the connector can be easily rotated. Rotational alignment during connecting slows down the process and historically requires personnel around the riser during the process, a situation to be minimized in sour well operations. To solve this problem, a novel feature of the present invention is to ignore the objective of achieving a rotational lock as the vertical connection is being made. With the instant system the connection is initially left free to rotate during vertical connection. A rotational lock is triggered subsequently when the tool first experiences a rotational force. One particular method for practicing this system can be achieved through the use of spring loaded keys.
Thus, one aspect of the present invention includes a method for affording an anti-rotational connection that, unlike prior solutions, does not require rotational alignment of two connector tool sections prior to, or during, tool vertical connection. A subsequent anti-rotational connection is achieved by the use of spring loaded keys which spring out into receptor keyways after the quick vertical connection has been made. The connector sections are left free to rotate during make up. Only when exposed to a rotational force subsequently does the made up connector rotate slightly and then lock positively, allowing no further rotation.
In overview, the invention comprises a composite of concepts. An additional concept includes putting not only one but two independent release mechanisms in the connector tool, both able to be used for "hands-free" deployment. Pressure activation affords an effective method for implementing the two independent release mechanisms. A preferred embodiment of the invention includes, thus, two independent pressure activated, biased pistons, one restrained by springs, and the other by shear pins. Each piston can be designed to move at a predetermined pressure, each affording release of the connector sections.
Traditionally, as discussed above, there were limitations on the lengths of perforating guns that could be run on coil, as the guns usually have to be retrieved from a live well. This meant that a lubricator length was required that was at least as long as the guns run, and there was a limit to the length of a riser, or lubricator, that could be accommodated, on both land and offshore operations. As the running of long perforating guns on coiled tubing has become a growing business, an alternative deployment approach developed to deploy these guns in sections. Deployment systems developed for use with perforating gun modules that used downhole connectors that could be connected and disconnected "hands-free" inside a live wellhead, incurred the additional problem that they had no suitable contingency plan to allow for a connector failure, short of killing the well. In other words, if, during retrieval of perforating guns, one of the connectors were to fail to disconnect, there is no other safe course of action other than killing the well. Even then it is not possible to maintain two barriers in the well (standard oilfield requirement) as it is not possible to strip the guns and indeed they have no internal pressure barrier.
The present invention solves, in addition to other severe weakness of prior deployment systems, this lack of alternative release procedures in the event of a connector failure. The solution of the present design is to put two independent release mechanisms in the connector. If the primary release mechanism fails, then a second can be activated. The availability of this feature may eventually lead to this kind of system being the only system acceptable for use in some more regulated areas such as the North Sea.
In operation, a blowout preventor (BOP) on the well is replaced, if necessary, with a coiled tubing BOP. A coiled tubing BOP has a height of several feet. A deployment apparatus, which can comprise a modified standard BOP, designed in accordance with the present invention, is attached to the top of the coiled tubing BOP. The deployment apparatus has a height of several feet. Three rams are provided within a preferred embodiment of the deployment apparatus. The lower ram seals against and supports or holds, as with slips or slip teeth, a lower section of the connector tool. A portion of the lower universal connect/disconnect (UCD) section is designed to mate with the slips or slip teeth. A second sealing ram a foot or two higher up, seals against another portion of the UCD. A third ram, a foot or two higher up, operates as modified as a vertical height locating and horizontal position adjusting means.
Above the deployment apparatus is situated a gate valve. The gate valve can be a standard gate valve. A BOP modified to become a deployment apparatus provides for attachment to apparatus such as a gate valve. The gate valve occupies a foot or two of height. The gate valve is adapted to receive and sealingly mate with a pressure vessel frequently termed a "riser" or a "lubricator". This can be a standard riser or lubricator. The riser or lubricator may be about fifty feet (50') in height. Two different risers are used typically in a coiled tubing deployment system. The first riser is a wireline riser. The second riser is a coiled tubing riser. The wireline riser has a stuffing box at its top end to sealingly mate with a wireline coming out of the top of the riser. The coiled tubing riser has a stuffing box at its top designed to sealingly mate with coil tubing coming out of the top of the riser. It is not necessary to use a wireline riser. A coiled tubing riser can suffice.
BHA tools can be deployed in modular fashion for running with coiled tubing using the above coiled tubing BOP, deployment apparatus, gate valve and risers, as follows. The coiled tubing BOP, the deployment apparatus and the gate valve are installed. The gate valve is initially closed, forming a barrier at the surface against well fluid. (The coiled tubing BOP offers another barrier against well fluid at the surface.) The UCD has an upper section and a lower section, designed to be vertically and rotationally mated and unmated, or made up and broken. A wireline is connected to an upper UCD section with the wireline running through the stuffing box on the top of the wireline riser. The BHA to be run is broken down into modular lengths, such as thirty foot (30') lengths. A lower section of a UCD is screwed into, or made up into, the top of each module. An upper section of a UCD is screwed into, or made up into, the bottom of each modular tool portion, (save and except the lowest modular tool portion.)
The lowest modular tool portion, having a lower section of a UCD affixed to its top, is made up with the upper section of a UCD connected to the wireline. The modular tool, and wireline are then pulled into the wireline riser. The wireline riser is raised and installed over the gate valve. The gate valve is opened and the modular tool section is lowered via the wireline through the deployment apparatus and coiled tubing BOP. An upper vertical locating ram of the deployment apparatus is closed and the tool is pulled up until a shoulder of the lower UCD section attached to the tool module rests against a shoulder of the vertically locating deployment ram. The lower sealing slip ram and upper sealing ram are then closed about the lower UCD section. The rams both close around predesigned portions of the vertically located UCD section. Pressure is applied to an annular chamber defined in the deployment apparatus between the sealing rams. The vertical connection between the lower UCD section attached to the tool module and the upper UCD section attached to the wireline is broken by means of the pressure. Pressure in the chamber defined between the two deployment sealing rams causes a piston and dog to shift within the UCD. The upper vertical locating ram is relaxed. The wireline with its attached upper UCD section is raised into the wireline riser. The gate valve is closed. The wireline riser is disconnected from the gate valve and returned to pick up a second tool module. The wireline riser is again reinstalled on top of the gate valve with the second tool module. This time the riser contains the wireline with its attached upper UCD section mated to a lower UCD section attached to the top of the second modular unit of the BHA. The second modular BHA unit is attached, as discussed above, at its bottom to an upper UCD section. Upon mating of the riser with the gate valve, the gate valve is opened and the second modular tool unit is lowered. The second unit with its upper UCD section attached to its bottom portion is lowered to rest upon a shoulder of the lower UCD section attached to the upper portion of the initial tool module, the lower section being held in the slip and sealing rams. With the upper and lower UCD sections vertically aligned or actually mated, the pressure is bled off that has overcome and moved a spring biased piston in the UCD. When the pressure is released, the spring biased piston returns to its initial position and a dog attached to the piston forces a collett mechanism in the upper UCD section into a mating detent mechanism of the bottom UCD section. Thereby, the upper and lower UCD sections are vertically united. The union is, at this point, independent of the angular rotation of either UCD section, since the detent of the bottom section is circular. The deployment apparatus rams are now released and the first and second tool modules are lowered such that the lower UCD section attached to the top of the second tool module is in the deployment apparatus. The vertical height ram is closed, and the lower tool section is pulled upwardly until its vertical height is adjusted. The sealing and slip rams are now closed around portions of the lower UCD section. Pressure is applied, as above, to move the piston and dog and permit a disconnect of the upper UCD section connected to the wireline from the lower UCD section affixed to the top of the tool string. (The pressure moves the piston and dog to a position where the collett can free itself, with a suitable pull, from its mating detent mechanism.) The vertical alignment ram is relaxed, and the wireline and upper UCD section are pulled into the wireline riser. The gate valve is shut. The wireline riser is unmated from the gate valve and returned to the ground to pick up a third tool module, it also having a lower UCD section affixed to its top and an upper UCD section affixed to its bottom. The procedure is continued until the time comes to connect the upper tool module to the coiled tubing unit. At this point the coiled tubing riser, usually only a few feet high, is deployed in place of the wireline riser. Using the coil tubing to function as the wireline, the procedure to affix the last tool module to the coiled tubing head is similar to the above, the bottom end of the coiled tubing being connected to an upper UCD section. The coiled tubing riser will remain mated with the gate valve during tool operation downhole.
One feature of the UCD is that it makes and unmakes by virtue of an external pressure triggering a biased piston mechanism. Increasing pressure in a chamber between two sealing rams within a deployment apparatus increases pressure in a chamber on one side of the piston. When the pressure is increased sufficiently, the piston overcomes both its bias as well as any opposing fluid pressure and moves. The translation of the piston in its chamber moves with it a dog. Movement of the dog permits a collet to unset and release from a detent. The collet advantageously forms a portion of an upper UCD section and the detent advantageously forms a portion a lower UCD section. Movement of the piston back lodges the collet, if in place, in the detent by means of the dog.
Interior sections of the upper and lower UCD sections preferably contain mating means so as to form interior pressure seals as the upper and lower sections are mated.
The UCD sections are preferably designed to mate the collets into the detent without reference to relative axial rotation between the sections. Further means are provided such that upon receipt of an initial rotational torque by the UCD tool, keys fixing the relative rotational location of the lower section to the upper section lock into place so that the mated UCD can now transmit rotational torque.
Ports may be provided through the outer wall of the lower UCD section such that pressure in the deployment apparatus chamber defined between two deployment sealing rams can be transmitted to an interior chamber around the piston.
Another feature of the invention includes use of a pair of external pressure ports to develop pressure differentials to release a tool connection. The tool preferably includes two independent pressure triggered release mechanisms in it.